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Posted to commits@airflow.apache.org by "Marko Kattelus (Jira)" <ji...@apache.org> on 2020/03/16 13:24:00 UTC
[jira] [Created] (AIRFLOW-7071) LocalExecutor queuing behaviour
Marko Kattelus created AIRFLOW-7071:
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Summary: LocalExecutor queuing behaviour
Key: AIRFLOW-7071
URL: https://issues.apache.org/jira/browse/AIRFLOW-7071
Project: Apache Airflow
Issue Type: Improvement
Components: scheduler
Affects Versions: 1.10.8
Reporter: Marko Kattelus
This is about question about possible improvement of queuing behaviour related to LocalExecutor.
Here is example log from our test system.
{code}
14:22:45 scheduler.1 | [2020-02-20 14:22:45,015] \{base_executor.py:122} DEBUG - 8 running task instances
14:22:45 scheduler.1 | [2020-02-20 14:22:45,015] \{base_executor.py:123} DEBUG - 0 in queue
14:22:45 scheduler.1 | [2020-02-20 14:22:45,015] \{base_executor.py:124} DEBUG - 0 open slots
14:22:45 scheduler.1 | [2020-02-20 14:22:45,016] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
14:22:47 scheduler.1 | [2020-02-20 14:22:47,200] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_17_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,200] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_16_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,201] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_15_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,202] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_14_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,202] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_13_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:122} DEBUG - 8 running task instances
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:123} DEBUG - 5 in queue
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:124} DEBUG - 0 open slots
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
14:22:47 scheduler.1 | [2020-02-20 14:22:47,204] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_4_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:47 scheduler.1 | [2020-02-20 14:22:47,205] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_19_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:122} DEBUG - 6 running task instances
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:123} DEBUG - 0 in queue
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:124} DEBUG - 2 open slots
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
14:22:49 scheduler.1 | [2020-02-20 14:22:49,129] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_1_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:49 scheduler.1 | [2020-02-20 14:22:49,130] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_3_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:49 scheduler.1 | [2020-02-20 14:22:49,131] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_6_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:51 scheduler.1 | [2020-02-20 14:22:51,136] \{base_executor.py:122} DEBUG - 3 running task instances
14:22:51 scheduler.1 | [2020-02-20 14:22:51,136] \{base_executor.py:123} DEBUG - 0 in queue
14:22:51 scheduler.1 | [2020-02-20 14:22:51,136] \{base_executor.py:124} DEBUG - 5 open slots
14:22:51 scheduler.1 | [2020-02-20 14:22:51,137] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
14:22:53 scheduler.1 | [2020-02-20 14:22:53,104] \{base_executor.py:122} DEBUG - 3 running task instances
14:22:53 scheduler.1 | [2020-02-20 14:22:53,104] \{base_executor.py:123} DEBUG - 0 in queue
14:22:53 scheduler.1 | [2020-02-20 14:22:53,105] \{base_executor.py:124} DEBUG - 5 open slots
14:22:53 scheduler.1 | [2020-02-20 14:22:53,105] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
14:22:53 scheduler.1 | [2020-02-20 14:22:53,105] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_5_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:122} DEBUG - 2 running task instances
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:123} DEBUG - 0 in queue
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:124} DEBUG - 6 open slots
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
14:22:55 scheduler.1 | [2020-02-20 14:22:55,112] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_10_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:57 scheduler.1 | [2020-02-20 14:22:57,263] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'load_dag_test_6_entity_5_2_45', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,264] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_17_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,265] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_16_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,265] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_15_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,266] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_14_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,266] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_13_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,267] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_12_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,267] \{base_executor.py:58} INFO - Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_11_1', '2020-02-20T14:18:01.743479+00:00', '--local', '--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,268] \{base_executor.py:122} DEBUG - 1 running task instances
14:22:57 scheduler.1 | [2020-02-20 14:22:57,268] \{base_executor.py:123} DEBUG - 8 in queue
14:22:57 scheduler.1 | [2020-02-20 14:22:57,268] \{base_executor.py:124} DEBUG - 7 open slots
14:22:57 scheduler.1 | [[2020-02-20 14:22:57,2812020-02-20 14:22:57,281] \{] {local_executor.py:base_executor.py:85} INFO133} DEBUG - - Calling the QueuedLocalWorker<class 'airflow.executors.local_executor.LocalExecutor'> running sync method
14:22:57 scheduler.1 | [2020-02-20 14:22:57,282] \{base_executor.py:157} DEBUG - Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_18_1', datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC, GMT, +00:00:00, STD]>), 1)
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:122} DEBUG - 7 running task instances
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:123} DEBUG - 0 in queue
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:124} DEBUG - 1 open slots
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:133} DEBUG - Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync method
{code}
The issue is that implementation clears queue and ordering is even so that LocalExecutor may been kept idle for no reason.
E.g.
# 8 running task instances 0 in queue 0 open slots
# 5 new tasks pushed to queue
# 2 tasks get ready
# 6 running task instances 0 in queue 2 slots open
# 3 tasks get ready
# 3 running task instances 0 in queue 5 open slots
# 1 tasks get ready
# 2 running task instances 0 in queue 6 open slots
# 8 new tasks pushed to queue
# 1 running task instances 8 in queue 7 open slots
# 1 task get ready
# 7 running task instances 0 in queue 1 slots open
So depending how often dag get rescheduled it might take long before we get more tasks for LocalExecutor. Also it feels that now some other dags may get scheduled just at the time when some tasks get ready and then kind of take place of tasks queued before because those are always removed at then end of every scheduler loop.
So would it be beneficial to keep queued tasks in local executor queue so that LocalExecutor can start processing next task as soon as slot is available instead of waiting until dag get scheduled next time.
Also as seen in 10,11,12 it seems that ordering of operations in LocalExecutor heartbeating cause that actually after scheduler loop slots got available are not filled all. Only those slots get used which are available before current heartbeating or at least it looks like it.
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